powerpc64/ftrace: Implement support for ftrace_regs_caller()
With -mprofile-kernel, we always save the full register state in ftrace_caller(). While this works, this is inefficient if we're not interested in the register state, such as when we're using the function tracer. Rename the existing ftrace_caller() as ftrace_regs_caller() and provide a simpler implementation for ftrace_caller() that is used when registers are not required to be saved. Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Naveen N. Rao
committed by
Michael Ellerman
Michael Ellerman
parent
9ef4042364
commit
ae30cc05be
@@ -357,6 +357,8 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
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{
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unsigned int op[2];
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void *ip = (void *)rec->ip;
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unsigned long entry, ptr, tramp;
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struct module *mod = rec->arch.mod;
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/* read where this goes */
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if (probe_kernel_read(op, ip, sizeof(op)))
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@@ -368,19 +370,44 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
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return -EINVAL;
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}
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/* If we never set up a trampoline to ftrace_caller, then bail */
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if (!rec->arch.mod->arch.tramp) {
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/* If we never set up ftrace trampoline(s), then bail */
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#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
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if (!mod->arch.tramp || !mod->arch.tramp_regs) {
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#else
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if (!mod->arch.tramp) {
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#endif
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pr_err("No ftrace trampoline\n");
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return -EINVAL;
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}
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#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
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if (rec->flags & FTRACE_FL_REGS)
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tramp = mod->arch.tramp_regs;
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else
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#endif
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tramp = mod->arch.tramp;
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if (module_trampoline_target(mod, tramp, &ptr)) {
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pr_err("Failed to get trampoline target\n");
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return -EFAULT;
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}
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pr_devel("trampoline target %lx", ptr);
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entry = ppc_global_function_entry((void *)addr);
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/* This should match what was called */
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if (ptr != entry) {
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pr_err("addr %lx does not match expected %lx\n", ptr, entry);
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return -EINVAL;
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}
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/* Ensure branch is within 24 bits */
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if (!create_branch(ip, rec->arch.mod->arch.tramp, BRANCH_SET_LINK)) {
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if (!create_branch(ip, tramp, BRANCH_SET_LINK)) {
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pr_err("Branch out of range\n");
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return -EINVAL;
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}
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if (patch_branch(ip, rec->arch.mod->arch.tramp, BRANCH_SET_LINK)) {
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if (patch_branch(ip, tramp, BRANCH_SET_LINK)) {
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pr_err("REL24 out of range!\n");
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return -EINVAL;
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}
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@@ -388,14 +415,6 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
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return 0;
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}
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#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
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int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
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unsigned long addr)
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{
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return ftrace_make_call(rec, addr);
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}
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#endif
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#else /* !CONFIG_PPC64: */
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static int
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__ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
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@@ -472,6 +491,137 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
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#endif /* CONFIG_MODULES */
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}
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#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
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#ifdef CONFIG_MODULES
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static int
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__ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
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unsigned long addr)
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{
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unsigned int op;
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unsigned long ip = rec->ip;
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unsigned long entry, ptr, tramp;
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struct module *mod = rec->arch.mod;
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/* If we never set up ftrace trampolines, then bail */
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if (!mod->arch.tramp || !mod->arch.tramp_regs) {
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pr_err("No ftrace trampoline\n");
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return -EINVAL;
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}
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/* read where this goes */
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if (probe_kernel_read(&op, (void *)ip, sizeof(int))) {
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pr_err("Fetching opcode failed.\n");
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return -EFAULT;
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}
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/* Make sure that that this is still a 24bit jump */
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if (!is_bl_op(op)) {
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pr_err("Not expected bl: opcode is %x\n", op);
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return -EINVAL;
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}
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/* lets find where the pointer goes */
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tramp = find_bl_target(ip, op);
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entry = ppc_global_function_entry((void *)old_addr);
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pr_devel("ip:%lx jumps to %lx", ip, tramp);
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if (tramp != entry) {
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/* old_addr is not within range, so we must have used a trampoline */
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if (module_trampoline_target(mod, tramp, &ptr)) {
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pr_err("Failed to get trampoline target\n");
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return -EFAULT;
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}
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pr_devel("trampoline target %lx", ptr);
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/* This should match what was called */
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if (ptr != entry) {
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pr_err("addr %lx does not match expected %lx\n", ptr, entry);
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return -EINVAL;
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}
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}
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/* The new target may be within range */
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if (test_24bit_addr(ip, addr)) {
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/* within range */
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if (patch_branch((unsigned int *)ip, addr, BRANCH_SET_LINK)) {
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pr_err("REL24 out of range!\n");
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return -EINVAL;
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}
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return 0;
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}
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if (rec->flags & FTRACE_FL_REGS)
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tramp = mod->arch.tramp_regs;
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else
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tramp = mod->arch.tramp;
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if (module_trampoline_target(mod, tramp, &ptr)) {
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pr_err("Failed to get trampoline target\n");
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return -EFAULT;
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}
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pr_devel("trampoline target %lx", ptr);
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entry = ppc_global_function_entry((void *)addr);
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/* This should match what was called */
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if (ptr != entry) {
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pr_err("addr %lx does not match expected %lx\n", ptr, entry);
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return -EINVAL;
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}
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/* Ensure branch is within 24 bits */
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if (!create_branch((unsigned int *)ip, tramp, BRANCH_SET_LINK)) {
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pr_err("Branch out of range\n");
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return -EINVAL;
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}
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if (patch_branch((unsigned int *)ip, tramp, BRANCH_SET_LINK)) {
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pr_err("REL24 out of range!\n");
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return -EINVAL;
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}
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return 0;
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}
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#endif
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int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
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unsigned long addr)
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{
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unsigned long ip = rec->ip;
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unsigned int old, new;
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/*
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* If the calling address is more that 24 bits away,
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* then we had to use a trampoline to make the call.
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* Otherwise just update the call site.
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*/
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if (test_24bit_addr(ip, addr) && test_24bit_addr(ip, old_addr)) {
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/* within range */
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old = ftrace_call_replace(ip, old_addr, 1);
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new = ftrace_call_replace(ip, addr, 1);
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return ftrace_modify_code(ip, old, new);
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}
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#ifdef CONFIG_MODULES
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/*
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* Out of range jumps are called from modules.
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*/
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if (!rec->arch.mod) {
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pr_err("No module loaded\n");
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return -EINVAL;
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}
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return __ftrace_modify_call(rec, old_addr, addr);
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#else
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/* We should not get here without modules */
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return -EINVAL;
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#endif /* CONFIG_MODULES */
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}
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#endif
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int ftrace_update_ftrace_func(ftrace_func_t func)
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{
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unsigned long ip = (unsigned long)(&ftrace_call);
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@@ -482,6 +632,16 @@ int ftrace_update_ftrace_func(ftrace_func_t func)
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new = ftrace_call_replace(ip, (unsigned long)func, 1);
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ret = ftrace_modify_code(ip, old, new);
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#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
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/* Also update the regs callback function */
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if (!ret) {
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ip = (unsigned long)(&ftrace_regs_call);
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old = *(unsigned int *)&ftrace_regs_call;
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new = ftrace_call_replace(ip, (unsigned long)func, 1);
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ret = ftrace_modify_code(ip, old, new);
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}
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#endif
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return ret;
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}
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